Testing of biological or chemical samples often requires a device for repeatedly subjecting multiple samples though a series of temperature cycles. To prepare, observe, test, and/or analyze an array of biological samples, one example of an instrument that may be utilized is a thermal cycler or thermocycling device, such as an end-point polymerase chain reaction (PCR) instrument or a quantitative, or real-time, PCR instrument. Such devices are used to generate specific temperature cycles, i.e. to set predetermined temperatures in the reaction vessels to be maintained for predetermined intervals of time.
Generally, thermal cycler systems include a sample block that has a plurality of reaction regions or sample block wells and that is configured to receive a plurality of samples contained in sample wells of a sample holder. The samples may be sealed within the wells of the sample holder via a lid, cap, sealing film or any other sealing mechanism between the wells and a heated cover. A variety of sample holders are used in thermal cycler systems including, for example, a multi-well microtiter plate, a micro card, or a through-hole array. Due to the variety of available sample holders, thermal cycler systems are often designed to be compatible with more than one type of sample holder. For example, sample blocks may be configured to receive a sample holder having either a full skirt or a semi-skirt. A full-skirted sample holder has skirting that generally extends on at least two opposite sides of the sample holder to the bottom portions of the sample wells, while the skirting of the semi-skirted sample holder leaves lower portions of the sample wells exposed. Designing a thermal cycler system compatible with sample holders having different designs often leads to inefficiencies depending on the actual sample holder used. To perform the PCR process successfully, efficiently, and accurately, these inefficiencies should be minimized to the greatest extent possible.
There is an increasing need to provide improved thermal cycler systems that address one or more of the above drawbacks.